Currently, users are able to use their mobile terminals in a variety of private and public locations such as airports, shopping malls, hospitals, conference facilities, trains etc., thanks to extensive coverage of wireless communication networks. However, depending upon particular circumstances, relating to a location and/or a time the mobile terminal is to be used, the use of the mobile terminal could be hazardous, at least temporarily, due to interaction with sensitive (site specific) electronic equipment. Therefore, there is a need for a mechanism, which in a critical situation or in a critical area allows the wireless communication network to dynamically switch off or limit radio emission from the mobile terminals, i.e. the transmitter thereof, such that site specific safety requirements are met.
In the following a few examples of critical situations are described. A reason for defining a critical situation or critical area may be that there is a high risk for adversely affecting some electronic equipment due to an actively transmitting mobile terminal. Thereby, potentially leading to some sort of accident or hazard. Another reason is different kinds of security threats or risks, which would apply in military or civil defense zones or the like. Within this invention disclosure all those scenarios, which are prone to accident or security risk due to mobile terminals actively transmitting information, are altogether termed as critical scenarios. Some well known examples of critical scenarios are take-off and landing of aircrafts, vicinity of operation theatres, military installations, nuclear power plants, sensitive government location and intelligence agencies and vicinity of immigration counters at port of entry.
In some form the use of mobile terminal is urged to be avoided in many of the above mentioned scenarios. Despite illustrious sign boards or repeated announcements forbidding the use of mobile terminals, the mobile terminals are inevitably used by some users. Irresponsible behavior of some of these users is not always the sole cause of not restricting use of the mobile terminal. Indeed such indications, announcements or messages, clearly forbidding the use of mobile phones, could be missed due to carelessness or sometimes due to medical disability (e.g. visual impairment) of some of the users. In a near future, onboard mobile operation will start allowing on-the-flight communication. Nevertheless, there may still be occasions when the transmitter of the mobile terminal should be turned off immediately.
Although mobile terminals typically operate in a well defined portion of the frequency band, emissions outside its operating bandwidth and band are unavoidable. Therefore, mobile terminals, as well as base stations, have to fulfill certain out of band (OOB) emission requirements. An objective of OOB emission requirements is to limit the interference caused by the transmitter (mobile terminal or base station) outside their respective operating bandwidths to adjacent carriers. In fact, all wireless communication standards (e.g. GSM, UTRAN, E-UTRAN, WLAN etc), clearly specify the OOB emission requirements to limit or at least reduce unwanted out of band emission. Out of band emission requirements as imposed by standard bodies of different countries or regions typically comprise maximum allowed levels of Adjacent Channel Leakage Ratio (ACLR), Spectrum Emission Mask (SEM) and spurious emissions. The specific definition and requirement level of these requirements may vary from one radio communication system to another. OOB emission levels tends to decay dramatically the further away from an operating band one moves, but the emission levels in adjacent frequency ranges are at least sometimes not completely eliminated.
Requirements for base stations are generally much tighter than those stipulated for mobile terminals. The reason is that a base station can afford to have more complex and sophisticated cut-off filters to suppress unwanted out of band emission. Furthermore, base stations operate at high output power. As a consequence, more relative suppression is needed compared to that of mobile terminals. For an UTRA mobile terminal and UTRA base stations, the OOB emission requirements are specified in TS 25.101 and TS 25.104, respectively. For E-UTRA mobile terminals and E-UTRA base stations, the OOB requirements are specified in TS 36.101 and TS 36.104, respectively. Depending upon the type, nature and frequency of operation of particular electronic equipment even a low level out of band emissions could have harmful effects in some situations. For instance, the reliability of aircraft navigational or medical devices, which generally require very high level of precision, could be adversely affected. Furthermore, transmitters of mobile terminals are typically more hazardous than those of base stations, since the latter is generally not installed (or located) in close proximity to a sensitive location or a critical situation (e.g. hospital etc). Secondly, as mentioned above, OOB emission requirements for base stations are much stricter than those for mobile terminals. Thus, in general, the impact of out of band emission due to base station on electronic equipment is lower than the impact of out of band emission due to mobile terminals. Notably, a mobile terminal may be located very close to a critical situation. Thereby, significant harm to the equipment may be caused. Furthermore, a plurality of mobile terminals may operate in the vicinity of sensitive electronic equipment. As a result, the adverse effects on sensitive electronic equipment from each mobile terminal may be enhanced.
By multimode mobile terminals, it is within this disclosure referred to mobile terminals supporting more than one band per radio access technology (multi-band) and/or supporting more than one radio access technology (multi-RAT). Today most mobile terminals are multimode enabled, which means they support more than one radio access technology and more than one frequency band per radio access technology. This is further elaborated below.
Most of the mobile terminals on the market support multiple bands even for the same radio access technology. A well known example is that of multi-band GSM terminal with 800/900/1800/1900 bands ensuring almost universal operation (i.e. in US, Europe, Asia and other regions). Tables 1 and 2 below give an overview of the frequency bands, which are currently standardized for UTRA FDD and E-UTRA, respectively.
TABLE 1UTRA FDD frequency bands [1-2]OperatingUL FrequenciesDL frequenciesBandUE transmit, Node B receiveUE receive, Node B transmitI1920-1980MHz2110-2170MHzII1850-1910MHz1930-1990MHzIII1710-1785MHz1805-1880MHzIV1710-1755MHz2110-2155MHzV824-849MHz869-894MHzVI830-840MHz875-885MHzVII2500-2570MHz2620-2690MHzVIII880-915MHz925-960MHzIX1749.9-1784.9MHz1844.9-1879.9MHzX1710-1770MHz2110-2170MHzXI1427.9-1452.9MHz1475.9-1500.9MHzXII698-716MHz728-746MHzXIII777-787MHz746-756MHzXIV788-798MHz758-768MHz
TABLE 2E-UTRA frequency bands [3-4]Uplink (UL)Downlink (DL)E-eNode B receiveeNode B transmitDu-UTRAUE transmitUE receiveplexBandFUL low-FUL highFDL low-FDL highMode11920 MHz-1980 MHz2110 MHz-2170 MHzFDD21850 MHz-1910 MHz1930 MHz-1990 MHzFDD31710 MHz-1785 MHz1805 MHz-1880 MHzFDD41710 MHz-1755 MHz2110 MHz-2155 MHzFDD5824 MHz-849 MHz869 MHz-894 MHzFDD6830 MHz-840 MHz875 MHz-885 MHzFDD72500 MHz-2570 MHz2620 MHz-2690 MHzFDD8880 MHz-915 MHz925 MHz-960 MHzFDD91749.9 MHz-1784.9 MHz1844.9 MHz-1879.9 MHzFDD101710 MHz-1770 MHz2110 MHz-2170 MHzFDD111427.9 MHz-1452.9 MHz1475.9 MHz-1500.9 MHzFDD12698 MHz-716 MHz728 MHz-746 MHzFDD13777 MHz-787 MHz746 MHz-756 MHzFDD14788 MHz-798 MHz758 MHz-768 MHzFDD17704 MHz-716 MHz734 MHz-746 MHzFDD331900 MHz-1920 MHz1900 MHz-1920 MHzTDD342010 MHz-2025 MHz2010 MHz-2025 MHzTDD351850 MHz-1910 MHz1850 MHz-1910 MHzTDD361930 MHz-1990 MHz1930 MHz-1990 MHzTDD371910 MHz-1930 MHz1910 MHz-1930 MHzTDD382570 MHz-2620 MHz2570 MHz-2620 MHzTDD391880 MHz-1920 MHz1880 MHz-1920 MHzTDD402300 MHz-2400 MHz2300 MHz-2400 MHzTDD
A typical multi-RAT mobile terminal supports multiple GSM and WCDMA. According to E-UTRAN standard a multi-RAT UE may support one or more of the following technologies: E-UTRAN FDD, E-UTRAN TDD, UTRAN FDD (WCDMA), UTRAN TDD, GSM, cdma2000 1x RTT and HRPD. A typical multi-RAT mobile terminal would largely depend upon market demand and network deployment scenarios.
The popularity of services allowing a position of the mobile terminal to be determined is on the rise. Furthermore, for safety purposes, mobile positioning is gradually becoming mandatory in several parts of the world. Several methods are in fact already standardized and could be used for positioning in mobile communication. Some well-known examples are satellite based positioning, fingerprinting, time of arrival based method, etc.
A fundamental solution, ensuring that electrical equipment in critical situations are not severely affected by emission from a mobile terminal in the vicinity thereof, is to manually switch off the mobile terminal. However, this cannot be guaranteed for all users, or mobile terminals, in all circumstances. Furthermore, smart phones, which are utilized for various other purposes, could not be used at all if completely turned off. On the market, there exist mobile terminals which allow the user to manually switch off the radio transmitter of the mobile terminal. In this manner, users may still use features of the mobile terminal, such as playing (local) games or managing calendars, since these features do not require the radio transceivers of the mobile terminal to be active. This solution does, however, not guarantee that emission from the mobile terminal is restricted, as conscious human interaction is required, which for obvious reasons can not always be assured.
In EP1052864, there is disclosed a method for controlling a mobile terminal. The mobile terminal receives mode change information for protecting a predetermined area, e.g. airplanes, hospitals or the like from disturbing use of the mobile terminal. When receiving such mode change information, the mobile terminal changes to a protection mode, in which at least the high frequency portion of the mobile terminal is switched off so that interference with other electronic systems within the predetermined area to be protected is avoided.